Refuse destructor furnace



1934- s. SYMINGTON REFUSEDESTRUCTOR FURNACE Filed Sept. 10, 1952 46% as w P A A I Q L Q Q 4 a K 7 M 1 INVENTOR t S ngton ATT ORNKY Patented Jan. 23, 1934 UNETED STATES REFUSE DESTRUCTOR FURNACE Scott Symington, London, England, assignor to Woodall-Duckham (1920) Limited Application September 10, 1932, Serial No. 632,620, and in Great Britain August 25, 1932 4 Claims.

One highly efficient type of refuse destructor furnace consists of a metal shell, constituting a shaft in which refuse is burnt; the shell is surrounded by a water jacket directly connected with 5 a boiler and forming an integral part of this.

A result of this departure from the usual firebrick construction is comparatively low temperatures in the planes of contact between the watercooled surfaces of the boiler jacket and the material inside the shaft, owing to the greater heat conductivity of the water-cooled surface as compared with that of firebrick.

An important product of a refuse destructor furnace is clinker, which has its best value when it is hardest. This hardness is, in turn, a function of the temperature to which the clinker has been exposed and owing to the rapid chilling effect of the water-cooled surface on the clinker, it follows that in the type of furnace described 20 above the skin hardness of the clinker may be lower than desirable.

It is an object of this invention to produce, by burning town refuse in a shaft furnace consisting of a metal shell surrounded by a water jacket, clinker which shall be comparable in skin hardness with clinker which has been produced from like material in a fire-brick shaft.

It has been found that in passing through a cylindrical shaft the refuse and the clinker produced from it remain in close contact with the wall of the shaft, so that when such wall is watercooled there is considerable chilling of the clinker by contact with said wall. It is accordingly a further object of the invention to cause the clinker to pass through the shaft without coming into close contact with the wall of the latter. I have found that the desired result, namely the improvement of the skin hardness of clinker produced in a shaft furnace of the kind in question, may be attained by departing from the cylindrical form of shaft and adopting one which has a downwardly increasing diameter.

This invention consists in the combination of a shaft furnace for burning town refuse, comprising a metal shaft having a downwardly increasing diameter and a water-jacket surrounding the shaft.

The increase in the diameter of the shaft need only be comparatively small when the surface with which the material is liable to come into contact is smooth, and by way of example it may be stated that a taper of approximately A per ft. has been found efficient for the purpose in view. Since olinkering occurs mainly in the lower part of the shaft, where the temperatures prevailing are higher than those towards the top of the shaft, the taper construction may, if desired, be confined to the lower part of the shaft.

A taper construction in the firebrick shaft of a destructor furnace is known, but it is for a reason which, in a sense, is the reverse of that prompting the i'present invention; it could not be foreseen that the drawback to the cylindrical steel shaft, which is of a nature different from that of the drawback to a cylindrical firebrick shaft, could be overcome by the taper construction, particularly by the small taper which proves effective.

In the accompanying drawing, there is shown in vertical section a furnace constructed in accordance with the invention.

The furnace is constructed of a cylindrical steel shell a and within this and co-axial therewith a steel shell 12, which is cylindrical as to the upper portion of its interior and slightly conical as to the lower part. The space between these shells is closed top and bottom by annular plates 0 and d, respectively, so as to form a water chamber 6 connected with a boiler. Water is supplied to this chamber through the pipe f which extends through the lower portion of the chamber. The water or steam outlet from the chamber is at g. h is a mud-cock and 2' a man-hole. The refuse to be burnt in the inner shell I), which constitutes the shaft of the furnace, is charged into the top of the shaft and is burnt by the blast injected through the pipes 7' extending through the lower part of the chamber e.

Having thus fully described the nature of the said invention and the best means I know of carrying the same into practical effect, I claim:

1. In a refuse destructor shaft furnace the combination of a metal shell, a second metal shell within, spaced from and coaxial with the first, means forming a water-tight closure to the space between the shells, means for admitting water to the said space and means for allowing escape of water or steam therefrom, the said second shell having an internal diameter which increases progressively downwards.

2. In a refuse destructor shaft furnace the combination of a metal shell, a second metal shell within, spaced from and co-axial with the first, means forming a water-tight closure to the space between the shells, means for admitting water to the said space and means for allowing escape of Water or steam therefrom, the said second shell having an internal diameter which increases procombination of a metal shell, a second metal shell within, spaced from and co-axial with the first, means forming a water-tight closure to the space between the shells, means for admitting water to the said space and means for allowing escape of water or steam therefrom, the lower part of the said second shell having an internal diameter which increases progressively downwards by an amount of the order of per ft.

SCOTT SYMINGTON. 

